Summary
- Where: The Slab, beyond a hidden‑ceiling path near the Bellway bench and an Apostate‑locked door.
- Gate: Key of Apostate from the Putrifield Ducts door route; other keys are used elsewhere in The Slab.
- Reward: Rune Rage (Silk Skill) unlock.
Location & Access
- Get the Key of Apostate in the ducts. See the ducts area page or the route tutorial for the cage location and approaches from Memorium or Bilewater.
- Return to The Slab. From the Bellway bench, head right into the chest room and jump through a hidden ceiling to reach the sealed path.
- Use the Apostate key on the door; the arena is beyond.
Note: You’ll likely use Indolent/Heretic keys during Slab exploration, but the First Sinner door specifically checks Apostate.
Moveset & Phases
Theme: A Weaver who “sews” runes and floods lanes with needles.
Phase 1
- Charge / Aerial Lunge: Gap close → diagonal slashes. Short‑hop or sidestep late; punish 1–2 hits.
- Cross‑stitch walls and Needle Rains: Horizontal walls, vertical falls, and diagonal spreads; avoid centerlines, weave lanes.
- Teleport / Skitter: Short reposition to reset spacing.
- Bind (heal): Interrupt on reaction; this is your freest damage.
Phase 2 (Enraged)
- Same kit at higher speed plus Rune Rage. She rises and seeds ~12 rune circles that detonate in spawn order—track the first circle and step forward through newly cleared space.
Strategy — Consistent Clear
- Spacing: Hold slight mid‑range to read Lunge and hop walls without getting cornered.
- Must‑punish: Always interrupt Bind; dash in and convert to damage.
- Rune Rage handling: Don’t outrun the chain. Move into freshly cleared circles, following the detonation order.
- Stability: Use short strings (2–3 hits). Reset rather than trading into needle spreads.
Recommended Loadouts
- Tools: One fast conversion for Bind punishes; a ranged chip (e.g., Cogfly‑style) to stabilize between strings.
- Crests: Mix mobility with one survivability option; a wider arc crest helps against aerial pokes.
- Silk Skill: Bring a comfortable skill for transitions; you can slot Rune Rage at the next bench after the win.
Reward — Rune Rage (Silk Skill)
- Effect: Marks enemies with silk runes that detonate, dealing AoE chip and multi‑target damage.
- Equip: Rest at a bench, open Crests & Tools, and slot your Silk Skill. Only one Silk Skill can be equipped at a time.
FAQ
Q: I opened a door near the Slab bell but didn’t find the boss. A: From the Bellway bench, enter the chest room on the right and jump through the hidden ceiling to reach the Apostate door route.
Q: Do I need all three prison keys for this? A: Not for this door. You’ll use Indolent/Heretic elsewhere, but First Sinner’s arena is locked by the Apostate key.
Q: Where exactly is the Apostate key? A: In the ducts, inside a smashable cage; routes exist from Memorium and Bilewater. See the ducts pages for details.
Sources
- YouTube — First Sinner boss and door route: https://www.youtube.com/watch?v=HvqJEYy8Ryg
- Community wikis and guides — Location notes (Slab bell bench → chest room → hidden ceiling) and Rune Rage behavior.
Open Interactive Map (All Areas)
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